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Message-ID: <725ac2a3-f526-44bc-a40c-c39ce0bd3046@foss.st.com>
Date: Thu, 29 Feb 2024 19:26:42 +0100
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Subject: Re: [PATCH v3 1/7] remoteproc: Add TEE support
Content-Language: en-US
To: Mathieu Poirier <mathieu.poirier@linaro.org>
CC: Bjorn Andersson <andersson@kernel.org>,
        Jens Wiklander
	<jens.wiklander@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        "Krzysztof
 Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley
	<conor+dt@kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <op-tee@lists.trustedfirmware.org>, <devicetree@vger.kernel.org>
References: <20240214172127.1022199-1-arnaud.pouliquen@foss.st.com>
 <20240214172127.1022199-2-arnaud.pouliquen@foss.st.com>
 <ZdjjnJyz7GSVDiPZ@p14s> <74b7a8a4-20e4-4210-8de5-0282ab3fbd9c@foss.st.com>
 <ZeCujRgH/odzU9og@p14s>
From: Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>
Organization: STMicroelectronics
In-Reply-To: <ZeCujRgH/odzU9og@p14s>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit

Hello Mathieu,

On 2/29/24 17:19, Mathieu Poirier wrote:
> Good morning,
> 
> On Wed, Feb 28, 2024 at 09:20:28AM +0100, Arnaud POULIQUEN wrote:
>> Hello Mathieu,
>>
>>
>> On 2/23/24 19:27, Mathieu Poirier wrote:
>>> On Wed, Feb 14, 2024 at 06:21:21PM +0100, Arnaud Pouliquen wrote:
>>>> From: Arnaud Pouliquen <arnaud.pouliquen@st.com>
>>>>
>>>> Add a remoteproc TEE (Trusted Execution Environment) driver
>>>> that will be probed by the TEE bus. If the associated Trusted
>>>> application is supported on secure part this device offers a client
>>>> interface to load a firmware in the secure part.
>>>> This firmware could be authenticated and decrypted by the secure
>>>> trusted application.
>>>>
>>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
>>>> ---
>>>> update from V2
>>>> - Use 'tee_rproc' prefix for all functions
>>>> - rename tee_rproc_get_loaded_rsc_table to tee_rproc_find_loaded_rsc_table
>>>> - redefine fonction to better match with the rproc_ops structure format
>>>> 	- replace 'struct tee_rproc' parameter by 'struct rproc' parameter
>>>> 	- rename 'rproc_tee_get_rsc_table()' to tee_rproc_get_loaded_rsc_table()
>>>> 	  and rework it to remove the cached_table management.
>>>> 	- introduce tee_rproc_get_context() to get the tee_rproc struct from the
>>>>           rproc struct
>>>> 	- rename tee_rproc_get_loaded_rsc_table() to tee_rproc_find_loaded_rsc_table()
>>>> - remove useless check on tee_rproc_ctx structure in tee_rproc_register()
>>>>   and tee_rproc_unregister()
>>>> - fix test on the return of tee_rproc_ctx = devm_kzalloc()
>>>> - remove useless includes and unused tee_rproc_mem structure.
>>>> ---
>>>>  drivers/remoteproc/Kconfig          |   9 +
>>>>  drivers/remoteproc/Makefile         |   1 +
>>>>  drivers/remoteproc/tee_remoteproc.c | 397 ++++++++++++++++++++++++++++
>>>>  include/linux/tee_remoteproc.h      | 102 +++++++
>>>>  4 files changed, 509 insertions(+)
>>>>  create mode 100644 drivers/remoteproc/tee_remoteproc.c
>>>>  create mode 100644 include/linux/tee_remoteproc.h
>>>>
>>>> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
>>>> index 48845dc8fa85..85299606806c 100644
>>>> --- a/drivers/remoteproc/Kconfig
>>>> +++ b/drivers/remoteproc/Kconfig
>>>> @@ -365,6 +365,15 @@ config XLNX_R5_REMOTEPROC
>>>>  
>>>>  	  It's safe to say N if not interested in using RPU r5f cores.
>>>>  
>>>> +
>>>> +config TEE_REMOTEPROC
>>>> +	tristate "trusted firmware support by a TEE application"
>>>> +	depends on OPTEE
>>>> +	help
>>>> +	  Support for trusted remote processors firmware. The firmware
>>>> +	  authentication and/or decryption are managed by a trusted application.
>>>> +	  This can be either built-in or a loadable module.
>>>> +
>>>>  endif # REMOTEPROC
>>>>  
>>>>  endmenu
>>>> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
>>>> index 91314a9b43ce..fa8daebce277 100644
>>>> --- a/drivers/remoteproc/Makefile
>>>> +++ b/drivers/remoteproc/Makefile
>>>> @@ -36,6 +36,7 @@ obj-$(CONFIG_RCAR_REMOTEPROC)		+= rcar_rproc.o
>>>>  obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
>>>>  obj-$(CONFIG_ST_SLIM_REMOTEPROC)	+= st_slim_rproc.o
>>>>  obj-$(CONFIG_STM32_RPROC)		+= stm32_rproc.o
>>>> +obj-$(CONFIG_TEE_REMOTEPROC)		+= tee_remoteproc.o
>>>>  obj-$(CONFIG_TI_K3_DSP_REMOTEPROC)	+= ti_k3_dsp_remoteproc.o
>>>>  obj-$(CONFIG_TI_K3_R5_REMOTEPROC)	+= ti_k3_r5_remoteproc.o
>>>>  obj-$(CONFIG_XLNX_R5_REMOTEPROC)	+= xlnx_r5_remoteproc.o
>>>> diff --git a/drivers/remoteproc/tee_remoteproc.c b/drivers/remoteproc/tee_remoteproc.c
>>>> new file mode 100644
>>>> index 000000000000..ac727e062d00
>>>> --- /dev/null
>>>> +++ b/drivers/remoteproc/tee_remoteproc.c
>>>> @@ -0,0 +1,397 @@
>>>> +// SPDX-License-Identifier: GPL-2.0-or-later
>>>> +/*
>>>> + * Copyright (C) STMicroelectronics 2023 - All Rights Reserved
>>>> + * Author: Arnaud Pouliquen <arnaud.pouliquen@st.com>
>>>> + */
>>>> +
>>>> +#include <linux/firmware.h>
>>>> +#include <linux/io.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/remoteproc.h>
>>>> +#include <linux/slab.h>
>>>> +#include <linux/tee_drv.h>
>>>> +#include <linux/tee_remoteproc.h>
>>>> +
>>>> +#include "remoteproc_internal.h"
>>>> +
>>>> +#define MAX_TEE_PARAM_ARRY_MEMBER	4
>>>> +
>>>> +/*
>>>> + * Authentication of the firmware and load in the remote processor memory
>>>> + *
>>>> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
>>>> + * [in]	 params[1].memref:	buffer containing the image of the buffer
>>>> + */
>>>> +#define TA_RPROC_FW_CMD_LOAD_FW		1
>>>> +
>>>> +/*
>>>> + * Start the remote processor
>>>> + *
>>>> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
>>>> + */
>>>> +#define TA_RPROC_FW_CMD_START_FW	2
>>>> +
>>>> +/*
>>>> + * Stop the remote processor
>>>> + *
>>>> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
>>>> + */
>>>> +#define TA_RPROC_FW_CMD_STOP_FW		3
>>>> +
>>>> +/*
>>>> + * Return the address of the resource table, or 0 if not found
>>>> + * No check is done to verify that the address returned is accessible by
>>>> + * the non secure context. If the resource table is loaded in a protected
>>>> + * memory the access by the non secure context will lead to a data abort.
>>>> + *
>>>> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
>>>> + * [out]  params[1].value.a:	32bit LSB resource table memory address
>>>> + * [out]  params[1].value.b:	32bit MSB resource table memory address
>>>> + * [out]  params[2].value.a:	32bit LSB resource table memory size
>>>> + * [out]  params[2].value.b:	32bit MSB resource table memory size
>>>> + */
>>>> +#define TA_RPROC_FW_CMD_GET_RSC_TABLE	4
>>>> +
>>>> +/*
>>>> + * Return the address of the core dump
>>>> + *
>>>> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
>>>> + * [out] params[1].memref:	address of the core dump image if exist,
>>>> + *				else return Null
>>>> + */
>>>> +#define TA_RPROC_FW_CMD_GET_COREDUMP	5
>>>> +
>>>> +struct tee_rproc__context {
>>>> +	struct list_head sessions;
>>>> +	struct tee_context *tee_ctx;
>>>> +	struct device *dev;
>>>> +};
>>>> +
>>>> +static struct tee_rproc__context *tee_rproc_ctx;
>>>> +
>>>> +static void prepare_args(struct tee_rproc *trproc, int cmd,
>>>> +			 struct tee_ioctl_invoke_arg *arg,
>>>> +			 struct tee_param *param, unsigned int num_params)
>>>> +{
>>>> +	memset(arg, 0, sizeof(*arg));
>>>> +	memset(param, 0, MAX_TEE_PARAM_ARRY_MEMBER * sizeof(*param));
>>>> +
>>>> +	arg->func = cmd;
>>>> +	arg->session = trproc->session_id;
>>>> +	arg->num_params = num_params + 1;
>>>> +
>>>> +	param[0] = (struct tee_param) {
>>>> +		.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
>>>> +		.u.value.a = trproc->rproc_id,
>>>> +	};
>>>> +}
>>>> +
>>>> +static struct tee_rproc *tee_rproc_get_context(struct rproc *rproc)
>>>> +{
>>>> +	struct tee_rproc *entry, *tmp;
>>>> +
>>>> +	list_for_each_entry_safe(entry, tmp, &tee_rproc_ctx->sessions, node) {
>>>> +		if (entry->rproc == rproc)
>>>> +			return entry;
>>>> +	}
>>>> +
>>>> +	return NULL;
>>>> +}
>>>> +
>>>> +int tee_rproc_load_fw(struct rproc *rproc, const struct firmware *fw)
>>>> +{
>>>> +	struct tee_ioctl_invoke_arg arg;
>>>> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
>>>> +	struct tee_rproc *trproc = tee_rproc_get_context(rproc);
>>>> +	struct tee_shm *fw_shm;
>>>> +	int ret;
>>>> +
>>>> +	if (!trproc)
>>>> +		return -EINVAL;
>>>> +
>>>> +	fw_shm = tee_shm_register_kernel_buf(tee_rproc_ctx->tee_ctx, (void *)fw->data, fw->size);
>>>> +	if (IS_ERR(fw_shm))
>>>> +		return PTR_ERR(fw_shm);
>>>> +
>>>> +	prepare_args(trproc, TA_RPROC_FW_CMD_LOAD_FW, &arg, param, 1);
>>>> +
>>>> +	/* Provide the address of the firmware image */
>>>> +	param[1] = (struct tee_param) {
>>>> +		.attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
>>>> +		.u.memref = {
>>>> +			.shm = fw_shm,
>>>> +			.size = fw->size,
>>>> +			.shm_offs = 0,
>>>> +		},
>>>> +	};
>>>> +
>>>> +	ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
>>>> +	if (ret < 0 || arg.ret != 0) {
>>>> +		dev_err(tee_rproc_ctx->dev,
>>>> +			"TA_RPROC_FW_CMD_LOAD_FW invoke failed TEE err: %x, ret:%x\n",
>>>> +			arg.ret, ret);
>>>> +		if (!ret)
>>>> +			ret = -EIO;
>>>> +	}
>>>> +
>>>> +	tee_shm_free(fw_shm);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(tee_rproc_load_fw);
>>>> +
>>>> +struct resource_table *tee_rproc_get_loaded_rsc_table(struct rproc *rproc, size_t *table_sz)
>>>> +{
>>>> +	struct tee_ioctl_invoke_arg arg;
>>>> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
>>>> +	struct tee_rproc *trproc = tee_rproc_get_context(rproc);
>>>> +	int ret;
>>>> +
>>>> +	if (!trproc)
>>>> +		return ERR_PTR(-EINVAL);
>>>> +
>>>> +	prepare_args(trproc, TA_RPROC_FW_CMD_GET_RSC_TABLE, &arg, param, 2);
>>>> +
>>>> +	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
>>>> +	param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
>>>> +
>>>> +	ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
>>>> +	if (ret < 0 || arg.ret != 0) {
>>>> +		dev_err(tee_rproc_ctx->dev,
>>>> +			"TA_RPROC_FW_CMD_GET_RSC_TABLE invoke failed TEE err: %x, ret:%x\n",
>>>> +			arg.ret, ret);
>>>> +		return ERR_PTR(-EIO);
>>>> +	}
>>>> +
>>>> +	*table_sz = param[2].u.value.a;
>>>> +
>>>> +	/* If the size is null no resource table defined in the image */
>>>> +	if (!*table_sz)
>>>> +		return NULL;
>>>> +
>>>> +	/* Store the resource table address that would be updated by the remote core. */
>>>> +	trproc->rsc_table = ioremap_wc(param[1].u.value.a, *table_sz);
>>>> +	if (IS_ERR_OR_NULL(trproc->rsc_table)) {
>>>> +		dev_err(tee_rproc_ctx->dev, "Unable to map memory region: %lld+%zx\n",
>>>> +			param[1].u.value.a, *table_sz);
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +	}
>>>> +
>>>> +	return trproc->rsc_table;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(tee_rproc_get_loaded_rsc_table);
>>>
>>> Here we are missing:
>>>
>>> tee_rproc_parse_fw()
>>
>> Please tell me if I'm wrong but the aim of this ops is to parse the firmware
>> before loading it in case of some resources shoukd be needed before.
>> but here to parse it we load. I'm not sure that this function makes sense here.
>>
> 
> The documentation for rproc_ops::parse_fw [1] indicate the operation
> is to extract the resource table from the firmware image, something that is
> echoed in by the implementation of rproc_elf_load_rsc_table().  No matter what
> the secure side needs or how it does it, this function should return the address
> of the resource table.  
> 
> [1]. https://elixir.bootlin.com/linux/v6.8-rc6/source/include/linux/remoteproc.h#L370
> 
>>> {
>>>         tee_rproc_load_fw()
>>>         resource_table = tee_rproc_get_loaded_rsc_table()
>>>
>>>         //check error conditions here
>>>
>>>         rproc->cached_table = resource_table;
>>>         rproc->table_ptr = resource_table;
>>
>> This seems to me that it is not possible regarding
>> the "memcpy(loaded_table, rproc->cached_table, rproc->table_sz)"[1] in
>> rproc_start() and the kfree(rproc->cached_table) [2] in rproc_shutdown(). We
>> would copy with the same source and destibnation address.
>> In this case a memory should be allocated for the rproc->cached_table.
>>
> 
> I touched base on how to fix the handling of the resource table in rproc_start()
> in an earlier reply, but because of the kfree() in rproc_shutdown, I agree
> rproc->cached_table should be set to NULL.  That said, there needs to be a
> detailed explanation of what is happening in rproc_start().
> 
>>
>>> }
>>>
>>> This is essentially the same as rproc_elf_load_rsc_table(). That way we don't
>>> need rproc_alt_fw_boot() and rproc_load_segments() doesn't have to be moved
>>> around. 
>>
>> The trusted application simply needs to know that if the firmware is
>>> already loaded, it has to return. 
>>
>> Today trying to load twice time is considered as an error in OP-TEE [3].
> 
> That can be fixed.
> 
>> As it is a constraint introduced by Linux, I would prefer treated it  in the Linux.
> 
> Things in the remoteproc subsystem have been working just fine for well over a
> decade.  I'd say this is introduced by contraints from an image that is handled
> by the secure world.
> 
>>
>> What about introduce a "fw_loaded" flag in tee_rproc__context?
> 
> I'd like to avoid that since the flag is associated with the specific way the
> trusted application works.  That flag surely won't apply, or new flags will be
> introduced, when another trusted application to handle the remote processor's
> firmware is introduced.
> 

Let's move in this direction, I can try to change the behaviour in OP-TEE on
Load and if it is not accepted we can rediscuss the use of a flag.

I will come back with a new version based on your proposals.

Thanks,
Arnaud

>>
>>
>> [1]
>> https://elixir.bootlin.com/linux/v6.8-rc6/source/drivers/remoteproc/remoteproc_core.c#L1289
>> [2]
>> https://elixir.bootlin.com/linux/v6.8-rc6/source/drivers/remoteproc/remoteproc_core.c#L2024
>> [3]
>> https://elixir.bootlin.com/op-tee/latest/source/ta/remoteproc/src/remoteproc_core.c#L896
>>
>>
>> Regards,
>> Arnaud
>>
>>>
>>>> +
>>>> +struct resource_table *tee_rproc_find_loaded_rsc_table(struct rproc *rproc,
>>>> +						       const struct firmware *fw)
>>>> +{
>>>> +	struct tee_rproc *trproc = tee_rproc_get_context(rproc);
>>>> +	size_t table_sz;
>>>> +
>>>> +	if (!trproc)
>>>> +		return ERR_PTR(-EINVAL);
>>>> +
>>>> +	if (!trproc->rsc_table)
>>>> +		trproc->rsc_table = tee_rproc_get_loaded_rsc_table(rproc, &table_sz);
>>>> +
>>>> +	return trproc->rsc_table;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(tee_rproc_find_loaded_rsc_table);
>>>> +
>>>> +int tee_rproc_start(struct rproc *rproc)
>>>> +{
>>>> +	struct tee_ioctl_invoke_arg arg;
>>>> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
>>>> +	struct tee_rproc *trproc = tee_rproc_get_context(rproc);
>>>> +	int ret;
>>>> +
>>>> +	if (!trproc)
>>>> +		return -EINVAL;
>>>> +
>>>> +	prepare_args(trproc, TA_RPROC_FW_CMD_START_FW, &arg, param, 0);
>>>> +
>>>> +	ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
>>>> +	if (ret < 0 || arg.ret != 0) {
>>>> +		dev_err(tee_rproc_ctx->dev,
>>>> +			"TA_RPROC_FW_CMD_START_FW invoke failed TEE err: %x, ret:%x\n",
>>>> +			arg.ret, ret);
>>>> +		if (!ret)
>>>> +			ret = -EIO;
>>>> +	}
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(tee_rproc_start);
>>>> +
>>>> +int tee_rproc_stop(struct rproc *rproc)
>>>> +{
>>>> +	struct tee_ioctl_invoke_arg arg;
>>>> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
>>>> +	struct tee_rproc *trproc = tee_rproc_get_context(rproc);
>>>> +	int ret;
>>>> +
>>>> +	if (!trproc)
>>>> +		return -EINVAL;
>>>> +
>>>> +	prepare_args(trproc, TA_RPROC_FW_CMD_STOP_FW, &arg, param, 0);
>>>> +
>>>> +	ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
>>>> +	if (ret < 0 || arg.ret != 0) {
>>>> +		dev_err(tee_rproc_ctx->dev,
>>>> +			"TA_RPROC_FW_CMD_STOP_FW invoke failed TEE err: %x, ret:%x\n",
>>>> +			arg.ret, ret);
>>>> +		if (!ret)
>>>> +			ret = -EIO;
>>>> +	}
>>>> +	if (trproc->rsc_table)
>>>> +		iounmap(trproc->rsc_table);
>>>> +	trproc->rsc_table = NULL;
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(tee_rproc_stop);
>>>> +
>>>> +static const struct tee_client_device_id stm32_tee_rproc_id_table[] = {
>>>> +	{UUID_INIT(0x80a4c275, 0x0a47, 0x4905,
>>>> +		   0x82, 0x85, 0x14, 0x86, 0xa9, 0x77, 0x1a, 0x08)},
>>>> +	{}
>>>> +};
>>>> +
>>>> +struct tee_rproc *tee_rproc_register(struct device *dev, unsigned int rproc_id)
>>>> +{
>>>> +	struct tee_client_device *tee_device;
>>>> +	struct tee_ioctl_open_session_arg sess_arg;
>>>> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
>>>> +	struct tee_rproc *trproc;
>>>> +	int ret;
>>>> +
>>>> +	/*
>>>> +	 * The device is not probed by the TEE bus. We ignore the reason (bus could be not yet
>>>> +	 * probed or service not available in the secure firmware)
>>>> +	 * Assumption here is that the TEE bus is not probed.
>>>> +	 */
>>>> +	if (!tee_rproc_ctx)
>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>> +
>>>> +	trproc =  devm_kzalloc(dev, sizeof(*trproc), GFP_KERNEL);
>>>> +	if (!trproc)
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +
>>>> +	tee_device = to_tee_client_device(tee_rproc_ctx->dev);
>>>> +	memset(&sess_arg, 0, sizeof(sess_arg));
>>>> +
>>>> +	/* Open session with rproc_tee load the OP-TEE Trusted Application */
>>>> +	memcpy(sess_arg.uuid, tee_device->id.uuid.b, TEE_IOCTL_UUID_LEN);
>>>> +
>>>> +	sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
>>>> +	sess_arg.num_params = 1;
>>>> +
>>>> +	param[0] = (struct tee_param) {
>>>> +		.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
>>>> +		.u.value.a = rproc_id,
>>>> +	};
>>>> +
>>>> +	ret = tee_client_open_session(tee_rproc_ctx->tee_ctx, &sess_arg, param);
>>>> +	if (ret < 0 || sess_arg.ret != 0) {
>>>> +		dev_err(dev, "tee_client_open_session failed, err: %x\n", sess_arg.ret);
>>>> +		return ERR_PTR(-EINVAL);
>>>> +	}
>>>> +
>>>> +	trproc->parent =  dev;
>>>> +	trproc->rproc_id = rproc_id;
>>>> +	trproc->session_id = sess_arg.session;
>>>> +
>>>> +	list_add_tail(&trproc->node, &tee_rproc_ctx->sessions);
>>>> +
>>>> +	return trproc;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(tee_rproc_register);
>>>> +
>>>> +int tee_rproc_unregister(struct tee_rproc *trproc)
>>>> +{
>>>> +	int ret;
>>>> +
>>>> +	ret = tee_client_close_session(tee_rproc_ctx->tee_ctx, trproc->session_id);
>>>> +	if (ret < 0)
>>>> +		dev_err(trproc->parent,	"tee_client_close_session failed, err: %x\n", ret);
>>>> +
>>>> +	list_del(&trproc->node);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(tee_rproc_unregister);
>>>> +
>>>> +static int tee_rproc_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
>>>> +{
>>>> +	/* Today we support only the OP-TEE, could be extend to other tees */
>>>> +	return (ver->impl_id == TEE_IMPL_ID_OPTEE);
>>>> +}
>>>> +
>>>> +static int tee_rproc_probe(struct device *dev)
>>>> +{
>>>> +	struct tee_context *tee_ctx;
>>>> +	int ret;
>>>> +
>>>> +	/* Open context with TEE driver */
>>>> +	tee_ctx = tee_client_open_context(NULL, tee_rproc_ctx_match, NULL, NULL);
>>>> +	if (IS_ERR(tee_ctx))
>>>> +		return PTR_ERR(tee_ctx);
>>>> +
>>>> +	tee_rproc_ctx = devm_kzalloc(dev, sizeof(*tee_ctx), GFP_KERNEL);
>>>> +	if (!tee_rproc_ctx) {
>>>> +		ret = -ENOMEM;
>>>> +		goto err;
>>>> +	}
>>>> +
>>>> +	tee_rproc_ctx->dev = dev;
>>>> +	tee_rproc_ctx->tee_ctx = tee_ctx;
>>>> +	INIT_LIST_HEAD(&tee_rproc_ctx->sessions);
>>>> +
>>>> +	return 0;
>>>> +err:
>>>> +	tee_client_close_context(tee_ctx);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +static int tee_rproc_remove(struct device *dev)
>>>> +{
>>>> +	struct tee_rproc *entry, *tmp;
>>>> +
>>>> +	list_for_each_entry_safe(entry, tmp, &tee_rproc_ctx->sessions, node) {
>>>> +		tee_client_close_session(tee_rproc_ctx->tee_ctx, entry->session_id);
>>>> +		list_del(&entry->node);
>>>> +		kfree(entry);
>>>> +	}
>>>> +
>>>> +	tee_client_close_context(tee_rproc_ctx->tee_ctx);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +MODULE_DEVICE_TABLE(tee, stm32_tee_rproc_id_table);
>>>> +
>>>> +static struct tee_client_driver tee_rproc_fw_driver = {
>>>> +	.id_table	= stm32_tee_rproc_id_table,
>>>> +	.driver		= {
>>>> +		.name		= KBUILD_MODNAME,
>>>> +		.bus		= &tee_bus_type,
>>>> +		.probe		= tee_rproc_probe,
>>>> +		.remove		= tee_rproc_remove,
>>>> +	},
>>>> +};
>>>> +
>>>> +static int __init tee_rproc_fw_mod_init(void)
>>>> +{
>>>> +	return driver_register(&tee_rproc_fw_driver.driver);
>>>> +}
>>>> +
>>>> +static void __exit tee_rproc_fw_mod_exit(void)
>>>> +{
>>>> +	driver_unregister(&tee_rproc_fw_driver.driver);
>>>> +}
>>>> +
>>>> +module_init(tee_rproc_fw_mod_init);
>>>> +module_exit(tee_rproc_fw_mod_exit);
>>>> +
>>>> +MODULE_DESCRIPTION(" TEE remote processor control driver");
>>>> +MODULE_LICENSE("GPL");
>>>> diff --git a/include/linux/tee_remoteproc.h b/include/linux/tee_remoteproc.h
>>>> new file mode 100644
>>>> index 000000000000..7c9e91e989ba
>>>> --- /dev/null
>>>> +++ b/include/linux/tee_remoteproc.h
>>>> @@ -0,0 +1,102 @@
>>>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>>>> +/*
>>>> + * Copyright(c) 2023 STMicroelectronics - All Rights Reserved
>>>> + */
>>>> +
>>>> +#ifndef TEE_REMOTEPROC_H
>>>> +#define TEE_REMOTEPROC_H
>>>> +
>>>> +#include <linux/tee_drv.h>
>>>> +#include <linux/firmware.h>
>>>> +#include <linux/remoteproc.h>
>>>> +
>>>> +struct rproc;
>>>> +
>>>> +/**
>>>> + * struct tee_rproc - TEE remoteproc structure
>>>> + * @node:		Reference in list
>>>> + * @rproc:		Remoteproc reference
>>>> + * @parent:		Parent device
>>>> + * @rproc_id:		Identifier of the target firmware
>>>> + * @session_id:		TEE session identifier
>>>> + * @rsc_table:		Resource table virtual address.
>>>> + */
>>>> +struct tee_rproc {
>>>> +	struct list_head node;
>>>> +	struct rproc *rproc;
>>>> +	struct device *parent;
>>>> +	u32 rproc_id;
>>>> +	u32 session_id;
>>>> +	struct resource_table *rsc_table;
>>>> +};
>>>> +
>>>> +#if IS_ENABLED(CONFIG_TEE_REMOTEPROC)
>>>> +
>>>> +struct tee_rproc *tee_rproc_register(struct device *dev, unsigned int rproc_id);
>>>> +int tee_rproc_unregister(struct tee_rproc *trproc);
>>>> +
>>>> +int tee_rproc_load_fw(struct rproc *rproc, const struct firmware *fw);
>>>> +struct resource_table *tee_rproc_get_loaded_rsc_table(struct rproc *rproc, size_t *table_sz);
>>>> +struct resource_table *tee_rproc_find_loaded_rsc_table(struct rproc *rproc,
>>>> +						       const struct firmware *fw);
>>>> +int tee_rproc_start(struct rproc *rproc);
>>>> +int tee_rproc_stop(struct rproc *rproc);
>>>> +
>>>> +#else
>>>> +
>>>> +static inline struct tee_rproc *tee_rproc_register(struct device *dev, unsigned int rproc_id)
>>>> +{
>>>> +	return ERR_PTR(-ENODEV);
>>>> +}
>>>> +
>>>> +static inline int tee_rproc_unregister(struct tee_rproc *trproc)
>>>> +{
>>>> +	/* This shouldn't be possible */
>>>> +	WARN_ON(1);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static inline int tee_rproc_load_fw(struct rproc *rproc,  const struct firmware *fw)
>>>> +{
>>>> +	/* This shouldn't be possible */
>>>> +	WARN_ON(1);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static inline int tee_rproc_start(struct rproc *rproc)
>>>> +{
>>>> +	/* This shouldn't be possible */
>>>> +	WARN_ON(1);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static inline int tee_rproc_stop(struct rproc *rproc)
>>>> +{
>>>> +	/* This shouldn't be possible */
>>>> +	WARN_ON(1);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static inline struct resource_table *
>>>> +tee_rproc_get_loaded_rsc_table(struct rproc *rproc, size_t *table_sz)
>>>> +{
>>>> +	/* This shouldn't be possible */
>>>> +	WARN_ON(1);
>>>> +
>>>> +	return NULL;
>>>> +}
>>>> +
>>>> +static inline struct resource_table *
>>>> +tee_rproc_find_loaded_rsc_table(struct rproc *rproc, const struct firmware *fw)
>>>> +{
>>>> +	/* This shouldn't be possible */
>>>> +	WARN_ON(1);
>>>> +
>>>> +	return NULL;
>>>> +}
>>>> +#endif /* CONFIG_TEE_REMOTEPROC */
>>>> +#endif /* TEE_REMOTEPROC_H */
>>>> -- 
>>>> 2.25.1
>>>>